1. Field of the Invention
This invention pertains generally to safety devices and methods for use with gas lines in the event of earthquakes or other disruptive conditions, and more particularly to a gas line safety evacuation system wherein, upon detection of seismic activity, fires, or other hazards, gas or other fluid is pumped out of gas lines and stored in storage tanks.
2. Description of the Background Art
The disruption of natural gas lines due to earthquakes or other events creates a substantial danger of fire and/or explosion due to escaped flammable gas which may subsequently be ignited by sparks or electrical discharge from damaged electric lines or other sources. Particularly, gas which has escaped from damaged lines often accumulates and mixes with air within buildings or other structures, and may lead to explosions.
A variety of safety systems have been developed to close off gas lines in response to detected seismic activity or other hazardous conditions in order to avoid the aforementioned risk of fire and explosion. Previously disclosed gas safety systems, however, are deficient in that they generally provide only for the closing of gas valves to seal off a gas source, such as a trunk line, and do not provide for removal of gas which is already present in gas lines downstream from the closed valves. In many situations, a considerable amount of gas remains in the lines after shutting off valves from the gas source, and this residual gas can still lead to fires and explosions. A system is known in the semiconductor fabrication industry, for use with hazardous gases such as silane and arsine, wherein the hazardous gases are evacuated from the gas lines and vented after the gas valves are shut off in response to an earthquake or other hazardous event. This system is deficient, however, in that the vented gases, which are highly toxic, create health and environmental hazards. Additionally, high purity industrial gas materials are frequently expensive and worth recovering or retrieving from the gas lines after shutdown.
Accordingly, there is a need for a gas line safety evacuation and storage apparatus and method which provides for evacuation of residual gas from gas lines, and which provides for storage of the gas evacuated from the gas lines. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in the background art.
The foregoing reflects the state of the art of which the applicant is aware and is tendered with the view toward discharging applicant's acknowledged duty of candor in disclosing information which may be pertinent in the examination of this application. It is respectfully stipulated, however, that the above background art does not teach or render obvious applicant's claimed invention.